An inverter power supply system is widely used to provide electric energy for an alternating current load. The inverter power supply system generally includes an inverter, where a direct current voltage receive end of the inverter receives a direct current voltage, converts the direct current voltage into an alternating current voltage, and outputs the alternating current voltage to a load through an alternating current voltage output end of the inverter. Generally, the direct current voltage receive end is connected to a rectifier, and the rectifier converts an alternating current voltage, such as a mains voltage, into the direct current voltage, and outputs the direct current voltage to the inverter through the direct current voltage receive end. When power consumption of a load loaded at the alternating current voltage output end of the inverter increases, a voltage dip of a direct current bus connected to the direct current voltage receive end of the inverter is caused. When an increase of the load is large, the voltage dip of the direct current bus is quick, leading to instability of the inverter power supply system. In order to prevent the voltage dip of the direct current bus from being excessively quick in this case, a common method is to increase capacitance of the direct current bus or improve the rectifier, to increase a response speed of the rectifier, so as to reduce an amplitude of the voltage dip of the direct current bus and a time needed for restoring a voltage of the direct current bus to a stable value. However, the method of increasing the capacitance of the direct current bus increases a size and a manufacturing cost of the inverter power supply system. Because a change of the voltage of the bus is a lagged inertial stage, even if the response speed of the rectifier is increased, the voltage of the direct current bus still has a large dip amplitude, and the time needed for restoring the voltage of the direct current bus to the stable value is still long.